Why 3M™ HFE Novec™ Engineered Fluid is the best solvent:
A brief history of cleaning solvents
CFC’s
In the 1980’s and prior, Freon TF (CFC-113) or Freon TMS (TF + 5.7% methanol) was the workhorse solvent for precision cleaning and vapor degreasing. It offered the following advantages:
- High purity
- Low “non-volatile residue” (what is left behind after the solvent evaporates)
- Non-flammability
- Good solvency (for most oils, flux and other soils)
- Good employee safety profile (high TLV/AEL employee exposure)
- Early environmental safety (not a VOC or smog contributor).
However, it was a slightly weaker solvent compared to other chlorinated solvents (TCE, Perc, 1,1,1 Trichlor).
HCFC’s
Then when the CFC’s were banned in 1992 due to ozone depletion factors, AGC Chemicals introduced the AK-225 line (AK225 MSDS) of HCFC’s (hydrochlorofluorocarbons) and DuPont introduced the HFC’s (hydrofluorocarbons). The AK-225 HCFC products, which contain chlorine on the molecule, were much better cleaners compared to the HFC’s. Therefore, the AK-225T solvent (boiling point 129°F) was the closest match to the previous Freon TMS (boiling point 105°F) with other very similar chemical and non-flammability properties. However, it did have very minimal ozone depletion potential of 0.02 compared to CFC-113 of 0.8.
At the time, it was the best drop-in replacement with reasonable pricing and toxicity values. Much political infighting was taking place at the U.S. Environmental Protection Agency (EPA) with all the chlorinated and other solvents hoping to be the best available. Since ozone depletion was the primary focus at the time, the EPA said they would allow the AK-225 HCFC but mandated phase out on January 1, 2015.
HFE
Enter the 3M™ HFE (hydrofluoroether) products as a drop-in replacement for AK-225. The high molecular weight of the HFE chemical means that it remains in the atmosphere for less than two weeks, and has zero ozone depletion potential (ODP). The 3M™ HFE chemistry also offers low GWP (global warming potential).
AK225 HCFC vs. 3M HFE Novec™ 72DA Comparison
| AK-225T HCFC | 3M™ Novec™ 72DA (replacement for AK225 due to 2015 phase out) |
|
| Composition | 87% 225ca/cb HCFC blend – non-flammable inerting properties and limited oil solvency | 30% HFE 7200 blend – non-flammable inerting properties only, no solvency for oils |
| 10% cyclohexane – to increase oils solvency | 68% 1,2 trans DCE (chlorinated solvent with inhibitors) – excellent high solvency for non-polar oils | |
| 3% ethanol – for polar oils – emulsifier soils removal | 2% Isopropanol – for polar oils – emulsifier soils removal | |
| Boiling point | 129°F | 111°F |
| Non-flammable – needed for vapor degreasing equipment | Yes | Yes |
| Employee safety | 50 ppm – ok, but higher is better | 200 ppm (that of the 1,2 trans DCE, HFE is higher – again, higher is better) |
| Environmental | ODP 0.02, not a VOC | No ODP (Ozone Depletion Potential), but the 1,2 DCE is a VOC (Volatile Organic Compound) |
| Chemical Stability | Very chemically stable for continued recycling in a vapor degreaser | Very chemically stable for continued recycling in a vapor degreaser |
| Component stability | Not an azeotrope, but very stable with minimal composition change over time | Is a true azeotrope, very stable with minimal composition change over time |
| Hazardous waste from the degreaser? | Only if what you clean off your parts is hazardous. | Only if what you clean off your parts is hazardous. |
| Cost | Lower cost than AK225T |
The evolution of more environmentally-friendly cleaning solvents has developed into excellent cleaning chemistries with little to no impact on the environment and employee exposure. Although the EPA push away from chlorinated solvents was difficult, it has led to much safer chemistries with similar cleaning effectiveness and power.
3M™ Novec™ HFE Engineered fluids are the solvent of choice for precision cleaning applications using vapor degreasers.
To learn more about solvent cleaning with 3M™ Novec™ HFE products, please see Solvent Cleaning with 3M Novec Engineered Fluids.
For price and ordering information, contact our chemical sales department using our web contact form, or call 612-392-2414, ext. 2.